1. Field of the Invention
The present invention relates to an improvement in a paper currency discriminating device and, more particularly, to a prevention of an illegal extraction of paper currency.
2. Description of the Related Art
The paper currency discriminating device has its paper currency transfer passage formed by two transfer plates which are arranged to face each other at a predetermined clearance. This paper currency transfer passage is arranged therein with: paper currency transfer means composed of belts, rollers and so on; and information detecting means for discriminating the paper currency such as magnetic heads and optical sensors. While the paper currency inserted into the paper currency discriminating device is being transferred by the paper currency transfer means, information for the discrimination is collected from the paper currency by the magnetic heads, the optical sensors and so on so that the genuineness/counterfeitness and kind of the paper currency may be decided on the basis of that discrimination information.
However, there are frequently tried the illegal operations, in which a thread or tape is attached to the paper currency so that the paper currency may be returned by the thread or tape after the decision of the genuineness of the paper currency and the output of the decision signal have been ended or after the introduction of the paper currency has been once ended. This raises a problem that the paper currency having triggered the output of a genuineness signal for allowing the sales conducts of an automatic vendor or the use of a game machine is returned back by the user himself although the genuineness signal was outputted from the paper currency discriminating device.
In order to solve this problem, there has been proposed the paper currency discriminating device, in which a shutter member for closing the paper currency transfer passage is arranged downstream of the information detecting means such as the magnetic heads or the optical sensors so that the decision signal is outputted after the paper currency transfer passage has been closed when the paper currency passed over the shutter member, as disclosed in Japanese Patent Laid-Open No. 130096/1979 and Japanese Utility Model Publications Nos. 33421/1980 and 4956/1973.
There also has been proposed a paper currency discriminating device, in which the shutter member for closing the paper currency transfer passage is arranged upstream of the information detecting means such as the magnetic heads and the optical sensors so that the collection of the discrimination information and the output of the decision signal may be executed while inhibiting the extraction of the inserted paper currency by holding it completely in the paper currency transfer passage, as disclosed in Japanese Utility Model Laid-Open No. 16363/1988 and Japanese Patent Laid-Open No. 32694/1976. However, either type of the proposals has an insufficient function to close the passage with the shutter member and has taken no consideration into the continuous insertion of paper currency although it is intended to prevent the extraction by a simple returning action to be effected by attaching the thread or tape to the paper currency. As a result, in the case of the continuous insertion of paper currency, the shutter member required to inhibit the extraction may be opened in response to the detection of insertion of the first paper currency so that the paper currency subsequently inserted may possibly be extracted by the illegal action.